Automatic flare igniter and counterbalanced flare stack

ABSTRACT

An elongated stack unit is mounted on a supporting base for swinging movement from a vertical operative position to a lowered position in which a burner assembly with electrical igniter at the top of the stack unit may be conveniently serviced. The lower end portion of the stack unit includes a liquid separator which collects liquid separated from the gas being burned. The liquid separator functions as a counterweight for normally maintaining the stack unit in its vertical position.

United States Patent 1 Sparrow et al. Sept. 4, 1973 1 AUTOMATIC FLARE lGNITER AND 2,734,562 2/1956 Haberle et al. 431 202 x COUNTERBALANCED FLARE STACK 3,488,924 1/1970 Reeve 55/92 X 2,802,521 8/1957 Campbell et al.. 431/202 X [76] Inventors: Donald Hugh Sparrow, Box 945;

Robert William Sparrow, Box 591, both of Leduc' Alberta; James Primary Examiner-Edward G. Favors Ernest sparrow H AttorneyFetherstonhaugh & Co. Edmonton, Alberta, all of Canada [22] Filed: May 6, 1971 1 1 Foreign Application Priority Data An elongated stack unit is mounted on a supporting Mar. 17, 1971 Canada l08028 base for swinging movement from a vertical operative position to a lowered position in which a burner assem- [52] US. Cl. 431/202, 23/277 C bly with electrical igniter at the top of the stack unit [51] F23d 13/20 may be conveniently serviced. The lower end portion [5 8] Field of Search 431/5, 202; of the stack unit includes a liquid separator which col- 23/277 C; 55/92 lects liquid separated from the gas being burned. The liquid separator functions as a counterweight for nor-' [56] References Cited mally maintaining the stack unit in its vertical position.

UNITED STATES PATENTS 3,134,424 5/1964 Zink et al. 43 l/5 X 9 Claims, 7 Drawing Figures mammal-m 3.756.765

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SHEET 3 BF 4 Kll D. H. SPARROW R. W. SPARROW .l. E. SPARROW NTS PATENT Pmmmw m. 5.756.165

SHEEI 3 BF 4 D H F76. 7 R. W. SPARROW J. E. SPARROW PArzmmw' 3.756.765

samuurg INVENTORS D. H. SP OW R. W. SP 0W J. E. SPARROW AUTOMATIC FLARE IGNITER AND COUNTERBALANCED FLARE STACK This invention relates to new and useful improvements in flare stacks of the general type used in the petroleum and natural gas industry for burning inflamable waste gases and, therefore, contributing to pollution control. Conventional flare stacks of this type may be 40 or more feet tall, and since the burner unit at the top of the stack requires periodic servicing, it usually is necessary for the service man to climb or be raised to the top of the stack in order to perform the servicing operation.

The principal object of the invention is to eliminate this disadvantage by the provision of a flare stack which is swingably mounted on a supporting base so that it may be quickly and easily swung from its normal vertical position to a lowered servicing position where the burner unit at the top of the stack is readily accessible from ground level.

In conjunction with the foregoing, another important object of the invention is to provide a stack which is counterweighted and thus counterbalanced to its normal vertical position, while tilting thereof to the servicing position is easily effected. Significantly, the counterweight is constituted by a liquid separator which is embodied in the lower end portion of the stack unit below the fulcrum thereof on the supporting base, the separator serving to collect liquid separated from incoming fluid so that only the gas component of the fluid passes through the stack pipe and is burned.

As such, the invention is particularly useful in installations where personnel is not in constant attendance to deal with situations involving sudden and unexpected surges of gas with oil or water, in which situations it is highly important that the gas be flared to eliminate, to as great an extent as possible, pollution of the atmosphere and the liquid be by-passed to the flare pit, or the like. As already noted, the liquid separator embodied in the lower end portion of the stack unit of the invention automatically accommodates such sudden surges of gas with liquid, and additionally functions as a counterweight for the tiltable stack unit itself.

Another important feature of the invention resides in the arrangement of the burner unit at the top of the stack, the same including a flare shield forproper mixing of the inflamable gas with air, and also including. electrical ignition means capable of being energized by a remotely located power source which may be actuated either manually or automatically at timed intervals to assure ignition of the escaping gas at all times.

The flare stack of the invention is simple in construction, highly efficient in operation, easy to service, economical to manufacture, and well suited to' withstand corrosive effects of gas at'the burner unit.

With the foregoing more important objects and features in view and such other objects and features which may become apparent as this specification proceeds, the invention will be understood from the following description taken in conjunction with the accompanying drawings wherein like characters of reference designate like parts and wherein:

FIG. 1 is a side elevational view of the flare stack according to the invention;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a top plan view;

FIG. 4 is an enlarged sectional detail, taken substantially in the plane of the line 4-4 in FIG. 2;

FIG. 5 is an enlarged fragmentary elevational view of the burner unit;

FIG. 6 is a plan view of the burner unit shown in FIG. 5; and

FIG. 7 is a perspective view showing a typical installation of the flare stack.

Referring now to the accompanying drawings in detail, the flare stack of the invention is designated generally by the reference numeral 10 and comprises a stack unit 11 which is swingably mounted on a supporting base 12. Conveniently, the base 12 may be of welded tubular construction and may have a four-sided substantially pyramidal form, with one side left open as at 12a in FIG. 3 to facilitate tilting of the flare stack unit from its normal vertical position to a lowered servicing position where a burner unit 13 at the top of the stack unit is conveniently accessible from ground level.

A A horizontal fulcrum shaft 14 is secured to the stack unit 11 intermediate the ends of the latter and is rotatably journalled in bearings 15 provided at the top of the base 12. This permits the stack unit to be swung in a vertical plane from its normal upright position to its lowered servicing position, as already noted.

The stack unit 11 includes a stack pipe 16 which carries the aforementioned burner unit 13 at the upper end thereof. Since the stack may be 40 or more feet tall, the pipe 16 preferably consists of a plurality of sections 16a, 16b, 16c which are separably connected together by suitable couplings 17 so that they may be taken apart and conveniently transported when the stack is moved from one location to another. The stack unit 11 also includes an elongated cylindrical housing 18 which is disposed below the fulcrum shaft 14. The lower end portion of the'stack pipe 16 extends axially into the upper end portion of the housing 18 and is perforated as at 19 so as to communicate with the interior of the housing, it being noted that the housing is substantially larger in diameter than the stack pipe. The lower end of the pipe 16 issecured in the housing 18 by brackets or straps 20 as shown in FIG. 4 and the pipe is also secured in the top wall of the housing as at 21, at which point the housing top wall may also be secured to the fulcrum shaft 14 in addition to securing of the pipe 16 to the fulcrum shaft as already described.

The housing 18 functions as a counterweight which facilitates easy and convenient lowering of the stack unit 11 to its servicing position, but biases the stack unit to its normally upright position when servicing has been completed. To prevent undesired swinging of the stack, positive locking means may be provided such as for example a locking bolt 22 which, as'shown in FIG. 1, is insertable in an apertured bracket- 23 secured'to the bottom of the base 12 and is receivable in another apertured bracket 24 secured to the lower end of the housing 18. In addition, a plurality of guy wires, one of which appears at 25 in FIG. 1, may extend from anchor points on the ground to eyes 26 provided on the stack pipe 16 at some distance above thefulcrum shaft 14.

. Of course, the locking bolt 22 is removed and the guy The portion of the housing 18 which contains the perforated lower end portion of the stack pipe 16 is provided at one side thereof with an inlet connection 28 for fluid which is primarily the gas to be burned but may contain liquid such as oil and/or water which has not been separated from the gas at a prior separating stage. As is shown in FIG. 4, the inlet 28 is offset laterally to one side of the diametric plane of the housing 18 so that swirling motion is imparted to the fluid as it enters the housing. This assists in agitating the fluid so that it is effectively separated into a gas component which enters the stack pipe 16 through the perforations 19 and passes upwardly through the stack pipe to be flared at the burner unit 13. The liquid component of the fluid flows into the lower end portion of the housing 18 which constitutes a collecting chamber for the liquid, assurance thus being had that the liquid does not interfere with proper flaring of the gas at the burner unit.

The lower portion of the housing, that is, the liquid collecting chamber, contains an overflow pipe 29 which has an open lower end spaced above the bottom of the housing 18 and is provided at its upper end with a laterally directed outlet 30, disposed at one side of the housing in upwardly spaced relation from the housing bottom. Thus, there is a constant level of collected liquid in the bottom portion of the housing, that is, up to the level of the outlet 30, which safeguards against any possibility of gas escaping from the housing through the outlet. As shown in the typical installation of FIG. 7, a fluid supply line 31 is connected to the inlet 28, while a liquid discharge line 32 extends from the outlet 30 to a suitable storage tank or flare pit 33.

The pressure at which the device can be operated is determined by the length of the overflow pipe 29, and near the lower end of that pipe holes 34 are provided to prevent any siphoning action.

Suitable fittings 35 are provided on the lower end portion of the housing to accommodate a sight gauge (not shown) by which the level of liquid in the housing may be determined. Also, the lower end of the housing is equipped with a drain plug 36 so that liquid in the housing may be periodically drained, such as when transporting the stack from one location to another or tilting it to its servicing position.

Attention is now directed to the burner unit 13 shown in detail in FIGS. and 6. This comprises an open-ended tubular flare shield 37 which is larger in diameter than the stack pipe 16 and is suitably mounted at the upper end of the stack pipe so that it surrounds the same and coacts therewith in defining an annular mixing chamber 38. The tubular shield 37 projects somewhat above the upper end of the stack pipe 16 and as gas is discharged from the pipe it becomes mixed with air entering through apertures 39 in the upper end portion of the shield, thus providing good mixing of air and gas for efficient burning.

Ignition is effected electrically by a pair of electrodes, namely, a live electrode 40 and a ground electrode 41, having tungsten tips 42 disposed above one side of the mixing chamber 38 in closely spaced relation to provide a sparking gap as will be apparent from FIG. 6. The ground electrode 41 is secured to the flare shield 37 while the live electrode 40 is supported by an electrode holder 43 carried by an insulating bracket 44 which has insulating qualities to withstand high voltages. The bracket 44 is secured to the stack pipe 16 by a clamp 45.

As shown in the typical installation of FIG. 7, ignition is energized by a power pack 46 disposed remotely from the flare stack, as for example on a pole 47, and connected by a stainless steel conductor 48 to the holder 43 of the live electrode 40, the power pack also having a suitable connection 49 to the ground. The power pack 46 provides a high voltage current supply, which may be on the order of 10,000 volts, for the live electrode 40 and as the current arcs across the spark gap between the electrode tips 42, the gas is ignited and effectively burned.

The apparatus is especially designed to resist corrosion which could otherwise result when the gas to be flared has a high content of hydrogen sulphide, as often is the case. Thus, as already mentioned, the electrode tips 42 are preferably made of tungsten and the high voltage conductor 48 is of stainless steel. Stainless steel orhigh tungsten steel is also preferably used for construction of the electrodes 40, 41, for the flare shield 37, and for the uppermost section 16c of the stack pipe.

The power pack 46 has a manual control for actuating ignition at will, but preferably it also has an automatic control, including a timer mechanism, which automatically actuates ignition at regular intervals, as for example, for five seconds every minute. This is particularly useful to assure continuous flaring when no attendant is present, and the provision of the flare shield 37 assures continuous burning even under severe weather conditions.

While in the foregoing there has been described and shown the preferred embodiment of the invention, various modifications and equivalents may be resorted to, within the spirit and scope of the invention as claimed.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A counterbalanced flare stack with liquid separator and igniting means, comprising in combination a supporting base, a horizontal fulcrum on said base, an elongated stack unit mounted intermediate its ends on said fulcrum for swinging movement from a vertical operative position to a lowered service position, said stack unit including a stack pipe and a separator housing being provided with an inlet for fluid having a gas component which is discharged through said stack pipe and a liquid component which is collected in said housing, electrical ignition means provided at the upper end of said stack pipe for igniting gas discharged therefrom, and means for discharging liquid from said separator housing, said housing being disposed below said fulcrum and constituting a counterweight for normally maintaining said stack unit in its vertical position.

2. The device as defined in claim 1 together with means on said base for positively locking said stack unit in its vertical position.

3. The device as defined in claim 1 wherein said stack pipe includes a plurality of pipe sections separably connected together.

4. The device as defined in claim 1 wherein said separator housing is cylindrical and of a larger diameter than said stack pipe, the lower end portion of the stack pipe extending axially in the upper end portion of said housing and being perforated to communicate with the interior of the housing, the lower end portion of the housing constituting a liquid collecting chamber.

5. The device as defined in claim 4 which is further characterized in that said fluid inlet communicates with that portion of said housing which contains said perforated lower end portion of said stack pipe, said inlet being offset laterally from the diametric plane of the housing whereby to impart swirling movement to fluid entering the housing.

6. The device as defined in claim 4 wherein said means for discharging liquid from said separator housing comprises an overflow pipe disposed in said liquid collecting chamber and having an open lower end'adjacent the bottom of said chamber, said overflow pipe also having an outlet at one side of said housing spaced upwardly from the bottom of said chamber.

7. The device as defined in claim 1 together with an open-ended tubular flare shield surrounding the upper end of said stack pipe in spaced relation therefrom to provide an annular mixing chamber between the stack pipe and the shield, said ignition means including a pair of electrodes mounted respectively on the stack pipe and on the flare shield.

8. The device as defined in claim 7 which is further characterized in that said electrodes are made of corrosion resistant metal.

9. The device as defined in claim 1 together with a remotely disposed electrical power pack in circuit with said ignition means, said power pack being characterized in that it energizes the ignition means automatically at timed intervals.

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1. A counterbalanced flare stack with liquid separator and igniting means, comprising in combination a supporting base, a horizontal fulcrum on said base, an elongated stack unit mounted intermediate its ends on said fulcrum for swinging movement from a vertical operative position to a lowered service position, said stack unit including a stack pipe and a separator housing being provided with an inlet for fluid having a gas component which is discharged through said stack pipe and a liquid component which is collected in said housing, electrical ignition means provided at the upper end of said stack pipe for igniting gas discharged therefrom, and means for discharging liquid from said separator housing, said housing being disposed below said fulcrum and constituting a counterweight for normally maintaining said stack unit in its vertical position.
 2. The device as defined in claim 1 together with means on said base for positively locking said stack unit in its vertical position.
 3. The device as defined in claim 1 wherein said stack pipe includes a plurality of pipe sections separably connected together.
 4. The device as defined in claim 1 wherein said separator housing is cylindrical and of a larger diameter than said stack pipe, the lower end portion of the stack pipe extending axially in the upper end portion of said housing and being perforated to communicate with the interior of the housing, the lower end portion of the housing constituting a liquid collecting chamber.
 5. The device as defined in claim 4 which is further characterized in that said fluid inlet communicates with that portion of said housing which contains said perforated lower end portion of said stack pipe, said inlet being offset laterally from the diametric plane of the housing whereby to impart swirling movement to fluid entering the housing.
 6. The device as defined in claim 4 wherein said means for discharging liquid from said separator housing comprises an overflow pipe disposed in said liquid collecting chamber and having an open lower end adjacent the bottom of said chamber, said overflow pipe also having an outlet at one side of said housing spaced upwardly from the bottom of said chamber.
 7. The device as defined in claim 1 together with an open-ended tubular flare shield surrounding the upper end of said stack pipe in spaced relation therefrom to provide an annular mixing chamber between the stack pipe and the shield, said ignition means including a pair of electrodes mounted respectively on the stack pipe and on the flare shield.
 8. The device as defined in claim 7 which is further characterized in that said electrodes are maDe of corrosion resistant metal.
 9. The device as defined in claim 1 together with a remotely disposed electrical power pack in circuit with said ignition means, said power pack being characterized in that it energizes the ignition means automatically at timed intervals. 